When an air-fuel mixture is combusted in an engine combustion chamber, some of the combusted gas may enter the engine crankcase via a small clearance between the cylinder walls and the piston rings. This gas may be referred to as blow-by gas. To prevent this untreated gas from being directly vented into the atmosphere, a crankcase ventilation system may be provided between the higher pressure crankcase and the lower pressure intake manifold to allow the blow-by gas to flow from the crankcase into the intake manifold and be mixed with fresh air. From here, the gas may be re-inducted into the combustion chamber for re-combustion.
Engine lubrication oil typically present in the crankcase during normal engine operation may become suspended and mix with the blow-by gas. However, combustion of the oil with the re-circulated blow-by gas may cause the net oil consumption of the engine to increase, and may degrade engine emission quality. To address these issues, oil separators have been developed to separate the oil content from the blow-by gas containing the oil mist. Oil separators may include various surfaces such as baffles and the like against which the oil and blow-by gas mixture may be impinged in order to cause the oil to drop out of the mixture. After separation, the oil is returned to the engine lubricating system while the blow-by gas is directed to the engine intake system as described.
Various oil separator designs may be used. One example design is disclosed in U.S. Pat. No. 5,562,087. The patent discloses an oil separator for blow-by gas with a nozzle that has a plurality of holes located in the air flow path of the blow-by gases disposed within a separate housing. The bottom of the housing includes a frustro-conical shaped recess for receiving oil that is separated from the blow-by gases. An oil drain fitting is disposed at a basin of the recess so that the oil received in the recess can be circulated back to the oil reservoir of the engine by connecting a tube or the like to the fitting.
The inventors herein have recognized several issues with this approach. One example issue is that this approach uses a separate housing for the specially designed nozzle. Another is that that this approach also uses an oil drain fitting and a connecting tube to re-circulate the separated oil back to the engine. What is needed is a simpler more cost efficient design that uses fewer parts and is easier to manufacture.
Embodiments in accordance with the present disclosure may provide an oil separator that may include a reservoir attached to a bottom of the oil separator to collect oil that passes from the oil separator. An outlet may be located on the reservoir and may be positioned to allow oil at or above the outlet to overflow from the reservoir and to flow, or drip, toward an engine cylinder head. The oil separator may also include a tube located at least partially inside the reservoir formed within the bottom to pass the oil into the reservoir.
Various example embodiments may include an engine crankcase ventilation system. The engine crankcase ventilation system may include a crankcase ventilation line configured to pass a mixture of oil and blow-by gas from the engine crankcase to an oil separation chamber. The oil separation chamber may be located above a cylinder head. The oil separation chamber may have a bottom. There may be a hole be in the bottom. A tube may protrude downwardly from the bottom and may have a first end surrounding the hole. The tube may also have a second end below the first end. A reservoir may be attached to the bottom and may surround the second end of the tube. An outlet may be included in the reservoir. The outlet may be located above the second end of the tube and may provide fluidic access from the reservoir to the cylinder head. In some example embodiments the bottom of the oil separation chamber and the tube may be made integrally. The reservoir may be made separately and may be attached to the bottom of the oil separation chamber.
In this way, an oil separator may be provided that may be easier to package and less expensive. Also in this way, a simplified anti-backflow valve may be constructed from the tube with one end submerged in the oil reservoir.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.